Serious exhaust valve ablation occurred at an aero piston engine during operating process due to the domestic high lead content fuel. Through micro metallographic analysis about the new

served and ablated exhaust valves from these engines

and based on the engine structural design and actual operating environment

a conclusion was drawn. Too high operating temperature making damage to the anti-corrosion protection layer on the exhaust valve's sealing area is the primary cause of the exhaust valve ablation

and the lead from the high lead content fuel deposited on the sealing area making the exhaust valves in poor-cooling condition is the predominant cause of hotter exhaust valves. The corresponding solution could improve the exhaust valve's cooling condition and decrease their operating temperature by running these engines with low lead content fuel to reduce the lead deposition. The practice shows that the anti-corrosion layer has been well protected and the fault of exhaust valve ablation is fixed in these engines.